1. Field of the Invention
This invention relates generally to closure cap constructions and more particularly to devices of the type having a cap body with an upstanding sealing peg which is received in the discharge orifice of a turnable twist cap carried on the cap body, to selectively close off the orifice in response to turning of the twist cap.
2. Description of the Related Art Including Information Disclosed Under 37 CFR .sctn..sctn.1.97-1.99
U.S. Pat. Nos. 3,216,630; 4,754,899 and 4,842,169 disclose various types of prior sealing-type twist cap constructions, all employing stopper pegs which have a generally cylindrical exterior surface configuration, preferably with rounded or beveled ends. These pegs provide a seal with the cylindrical walls of the discharge opening in the respective twist cap when the latter is placed in its fully seated, sealing position.
U.S. Pat. No. 3,549,060 illustrates a cap construction comprising a twist cap and employing a stopper peg having the configuration of a truncated cone. The surface of the cone seals against the walls of a discharge orifice in the twist cap.
In prior known caps having round discharge openings, where the product being dispensed is relatively viscous as in the case of ketchup or mustard, such product emerges in the shape of an elongate, thin bead. In use, the container is inverted and squeezed while the opening of the twist cap is positioned over or applied to the underlying food (i.e. hot dog, etc.).
Efforts have been made to provide cap structures with elongated openings, in which the product being dispensed would be discharged in the shape of a flat ribbon, as opposed to a bead of essentially round cross section. Such a ribbon shape has been considered desirable for use with mustard and ketchup, since it results in a more uniform application over the surface of the particular food to which it is being applied, be it hamburgers, hot dogs, or other food substances.
However, such attempts to achieve ribbon-type discharge characteristics have met with little commercial success. In particular, U.S. Pat. Nos. 3,285,479 and 3,369,707 both illustrate closure cap constructions having twist caps provided with slit-like openings in their ends, in which are received blade-like sealing members. The blade members are fixedly mounted on the undercap or base cap, and molded so as to have sufficient resiliency to enable their upper ends to deformably twist a limited extent without breaking, and without taking a permanent "set".
In U.S. Pat. No. '707, as the twist cap is unscrewed it rides up cam tracks provided on the base cap. The blade is normally of planar configuration and occupies the slit in the twist cap. During such turning the upper end portion of the blade is forcibly twisted and deformed, and eventually separates from the walls of the slit to provide a discharge passage for the product. Following use, the consumer re-seats the twist cap by turning it in a screwing-on direction, with the blade being restored to its initial planar shape by virtue of its resiliency, and re-establishing its position occupying the slit in the twist cap.
U.S. Pat. No. '479 discloses a similar arrangement, except that the twist cap is not raised by means of a cam track on the base cap. Instead, when the twist cap is turned in either direction, the blade becomes deformed as it is engaged by the inner conical surface of the twist cap, with the latter being cammed upwardly by such engagement, to the extent that the slit rises 1 above the blade and presents a clear opening for product discharge to occur. Re-sealing is accomplished by merely pushing downwardly on the twist cap. As this is done, the blade tends to restore the twist cap to is original circumferential position, and the walls of the slit slide over the upper end of the blade, to re-establish the seal.
A number of specific problems have occurred with dispensers of the type involving deformable stopper blades as described above. In particular, it is difficult to fabricate a sealing member in the form of a flat blade which is sufficiently resilient in order not to take a "set" especially following an extended period of use. In addition, attempts to make a plastic blade relatively stiff often resulted in the blade cracking or breaking during use, as opposed to merely flexing, as was desired. In the event of such breakage, the sealing function of the dispenser was completely lost, and there was the possibility of plastic fragments finding their way into the dispensed product. This was particularly troublesome where the substance being discharged was a food such as mustard, ketchup or other creamy material such as dressings and the like.
Even where breakage of the blade did not occur, smooth operation of the cap was difficult to attain. In particular, the use of the blade as a cam to shift the cap, as in U.S. Pat. No. '479, caused undue stresses on the blade, and it is believed that the design parameters inherent in prior blade type sealing caps do not lend themselves toward adaptation to a smooth and reliable operating mechanism for a dispensing cap.